腺癌性孤立性肺结节的^18F—FDG PET／CT表现

目的探讨腺癌性孤立性肺结节（ASPN）的^18F—FDG PET／CT显像特点。方法回顾分析35例ASPN的^18F-FDG PET／CT显像形态学和代谢特点，计算SUVmax，以公式（延迟显像SUVmax-早期显像SUVmax）／早期SUVmax×100％]计算△SUVmax。以SPSS11．5软件对数据分别行t检验、方差分析和Fisher确切概率法检验。结果（1）42．86％（15／35）ASPN呈典型的癌性肺结节表现（结节状FDG摄取增高），另有57．14％（20／35）ASPN FDG摄取呈片状、云雾状、肉眼无法辨认；结节状、云雾状、片状、肉眼无法辨认ASPN的SUVmax大小顺序递减，不同FDG摄取形态的ASPN早期和晚期SUVmax差异均有统计学意义，F=30．696和24．758，P均〈0．001。（2）54．29％（19／35）ASPN SUVmax≥2．5，45．71％（16／35）ASPN SUVmax〈2．5。（3）68．57％（24／35）ASPN呈实性密度结节，31．43％（11／35）ASPN呈“磨玻璃”密度结节；早期SUVmax分别为4．54±2．69、1．30±0．87，t=-5．234，P〈0．001。（4）延迟显像ASPN的SUVmax为422±3．52，高于早期显像的3．49±2．72（t=-4021，P〈0．1301）；延迟显像SUVmax是否增高与早期显像SUVmax的高低相关：94．74％（18／19）SUVmax≥2．5ASPN的△SUVmax为正值，仅56．25％（9／16）SUVmax〈2．5ASPN的△SUVmax为正值，P=0．013。（5）高分化ASPN SUVmax为1．70±1．51，低于中低分化ASPN的4．91±2．69，t=-3．951，P〈0．001，且△SUVmax〉0的比例（10／17）也低于中低分化ASPN（13／14），P=0．045。结论ASPNFDG摄取形态、代谢活性差异大，SUVmax〈2．5ASPN比例较高，△SUVmax对这类结节良恶性的鉴别有一定帮助。

The features of solitary pulmonary nodules of adenocarcinoma on 18F-FDG PET/CT

Objective To study the imaging characteristics of SPN of adenocarcinoma (ASPNs) on 18F-FDG PET/CT.Methods The morphological and metabolic features of 35 ASPNs on FDG PET/CT were retrospectively reviewed.SUVmax (SUV) was measured and ΔSUVmax was calculated according to ΔSUVmax =(SUVmax on delay imaging - SUVmax on early imaging)/SUVmax on early imaging × 100％.Statistical analysis was performed by software SPSS 11.5 using t-test,analysis of variance and Fisher exact test.Results ( 1 ) Fifteen ASPNs (42.86％,15/35) presented as nodular pattern on FDG PET imaging,while 20 (57.14％,20/35) as lamellar,cloudy or ill-defined patterns.The SUVmax of these ASPNs followed a descending order of nodular,lamellar,cloudy and ill:defined on both early and delay imaging (F =30.696 and 24.758,both P＜0.001).(2)There were 54.29％ (19/35) ASPNs with SUVmax ≥2.5 and 45.71％ (16/35) ASPNs with SUVmax ＜2.5.(3) Of 35 ASPNs,24(68.57％ ) were solid nodules and 11(31.43％) were ground glass nodules with SUVmax =4.54 ±2.69 and 1.30±0.87,respectively (t =-5.234,P ＜O.001 ).(4) The SUVmax of ASPNs on delay FDG imaging (4.22 ±3.52) was significantly higher than that on early imaging (3.49 ±2.72) (t =-4.021,P ＜0.001 ).However,SUVmax was dependent on SUVmax on the early imaging:when SUVmax ≥2.5,ΔSUVmax was positive in 94.74％ (18/19) of ASPNs; while SUVmax ＜2.5,ΔSUVmax was positive in 56.25％ (9/16) of ASPNs (P =0.013).(5) Of 31 ASPNs with cell differentiation data,there were 10/17 well-differentiated ASPNs and 13/14 poorly-differentiated ASPNs with positive ΔSUVmax ( P =0.045 ).The average SUVmax of well-differentiated ASPNs was significantly lower than that of poorly-differentiated ASPNs ( 1.70 ± 1.51 vs 4.91 ± 2.69,t =- 3.951,P ＜ 0.001 ).Conclusions The morphological and metabolic features of ASPNs are diversified.It is common for ASPN to present with SUVmax ＜ 2.5.ΔSUVmax may be helpful for differentiating malignant from benign SPNs.